An 11-year-old boy managed to board a flight to Rome on his own from Manchester Airport on Tuesday, without a passport or boarding pass.
Liam Corcoran passed through security without being checked, before making his way on to the Jet2.com flight, prompting an investigation by the UK airport.
According to the Manchester Evening News, Liam had run away from his mother during a shopping trip at Wythenshawe Civic Centre and made his own way to the airport.
A Manchester Airport spokesman said: "The boy went through full security screening so the safety of passengers and the aircraft was never compromised.
"We are now making preparations to ensure that his return to the UK is handled sensitively to avoid any distress."
He added that once passengers became aware that the boy was on his own, airline staff were alerted and the plane's captain informed the authorities.
The boy then remained on board after landing in Rome, and returned to Manchester on the same plane, where he was met by his mother.
A number of staff from Manchester Airport and Jet2.com have been suspended while the investigation takes place.